The conventional art has provided a share mode type inkjet head wherein voltage is applied to the electrode formed on a drive wall for separating the channel so that the drive wall is subjected to shear deformation, and the ink inside the channel is discharged out of the nozzle using the pressure generated inside the channel at this time. As this share mode type inkjet head, an inkjet head provided with the so-called harmonica type head chip is known, wherein the drive walls made up of piezoelectric elements and the channels are arranged alternately, and a channel aperture is arranged on each of the front side and rear side (Patent Document 1, 2).
In the case of an inkjet head having such a harmonica type head chip, ink is supplied into each channel from the rear side of the head chip. Accordingly, an ink manifold is connected to the rear side of the head chip, and the ink stored in this ink manifold is supplied to each channel.
Incidentally, as disclosed in the Patent Documents 1 and 2, the rear side of such a head chip is provided with a flow path regulating member for regulating the flow of ink into the channel by reducing the area of the aperture on the rear side of the channel.
FIG. 16 is a rear side view of the head chip 600 connected with a flow path regulating member 500. This drawing illustrates a harmonica type head chip 600 wherein the air channels 601 that do not emit ink and the ink channels 602 that emit ink are arranged alternately.
The flow path regulating member 500 utilizes a plastic film such as a sheet of polyimide having the size capable of covering almost all the surfaces on the rear side of the head chip 600. This film is bonded using adhesives as an epoxy adhesive and others. Here the rear side of each air channel 601 provided on the head chip 600 is completely blocked and an ink inlet 501 is formed so as to conform to each ink channel 602, thereby reducing the area of the aperture on the rear side (on the side supplied with ink) of each ink channel 602. The ink inlet 501 is provided, for example, by laser processing in such a way as to have a diameter smaller than that of the aperture on the rear side of the ink channel 602.
As described above, the area of the aperture on the rear side of the ink channel is reduced by the flow path regulating member 500, whereby easy control of the ink meniscus in the nozzle is ensured and high-speed drive is enabled. Thus, this arrangement provides the advantage of enhancing the drive characteristics.
When all the channels arranged on the head chip are ink channels, the ink inlets of the flow path regulating member are arranged so as to correspond to all the channels.    [Patent Document 1] Unexamined Japanese Patent Application Publication No. 2004-90374    [Patent Document 2] Unexamined Japanese Patent Application Publication No. 2006-35454
When the aforementioned flow path regulating member is connected to the rear side of the head chip, the coated adhesive may ooze from the ink inlet. This requires a large quantity of adhesive to be coated. This involves such problems as the excess adhesive flowing into the channel to block the channel and to cause emission failure, or ink flowing into the air channel due to insufficient coating of the adhesive, with the result that ink inlet is blocked by adhesive.
The connection electrode and others having been pulled out to the rear side of the head chip and having been formed therein will be covered by adhesive and electrical connection cannot be made. When this problem has occurred, it is necessary to remove the unwanted adhesive by dry etching or other means. This requires extra time and effort.
When the flow path regulating member is bonded by the adhesive oozing from the ink outlet, contact pressure cannot be easily applied from the flow path regulating member. The utmost caution must be taken when coating the adhesive and bonding the member. This gives rise to manufacturing difficulties.
Moreover, processing costs cannot be ignored when the ink inlet is processed by laser.
Further, when the area of the aperture on the rear side of the channel is to be reduced by the flow path regulating member, the ink inlet having a smaller area than that of the aperture on the rear side of the channel is formed approximately at the center of the aperture in the conventional flow path regulating member. Thus, the bubble having occurred inside the channel at the time of driving cannot easily get out of the ink inlet, and remains inside the channel. The bubble remaining inside the channel prevents a sufficient amount of the emission pressure from being applied to the ink, with the result that emission failure occurs.